Russian security forces stand guard following a suicide attack in the Volga River city of Volgograd. A suicide bomber killed at least 17 people on Dec. 29. / Vladimir Pakhomov, AFP/Getty Images

by USA TODAY

by USA TODAY

MOSCOW (AP) - Russia's counterterrorism agency has arrested two brothers suspected of assisting the suicide bombers who struck the southern city of Volgograd in late December.

The bombings of a train station and trolley bus in the Volga River city of Volgograd, which killed 34 people and wounded many more, heightened security fears ahead of the Winter Olympics in Sochi.

The National Anti-Terrorism Committee said Thursday in a statement that Magomednabi and Tagir Batirov were detained in Dagestan, a predominantly Muslim republic that has become the center of an Islamic insurgency. They are suspected of helping the suicide bombers travel to Volgograd, about 400 miles to the north.

The agency also released the names of the suspected bombers - Asker Samedov and Suleiman Magomedov - saying they were members of a terrorist group based in Dagestan.

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